Hey, Benjy asked me to post this for y’all to see, so here I go: Amongst team members having problems to get going with Pants, one saw some very confusing paths that suggest a mash-up between Python 2.7.0 and 3.9. This is the error they got:

(devtools) Moon-Kang's-MacBook-Pro:devtools moon$ make lint
./pants lint typecheck ::
15:14:58.25 [INFO] Initializing scheduler...
15:14:58.53 [INFO] Scheduler initialized.
15:15:10.94 [ERROR] Exception caught: (pants.engine.internals.scheduler.ExecutionError)
  File "/Users/moon/.cache/pants/setup/bootstrap-Darwin-x86_64/2.7.0_py39/lib/python3.9/site-packages/pants/bin/local_pants_runner.py", line 236, in _run_inner
    return self._perform_run(goals)
  File "/Users/moon/.cache/pants/setup/bootstrap-Darwin-x86_64/2.7.0_py39/lib/python3.9/site-packages/pants/bin/local_pants_runner.py", line 175, in _perform_run
    self._raise_on_error([t for _, t in throws])
  File "/Users/moon/.cache/pants/setup/bootstrap-Darwin-x86_64/2.7.0_py39/lib/python3.9/site-packages/pants/engine/internals/scheduler.py", line 506, in _raise_on_error
    raise ExecutionError(

Exception message: 1 Exception encountered:

  ProcessExecutionFailure: Process 'Find interpreter for constraints: CPython<4,>=3.6' failed with exit code 1.

This is a MacBook Pro running macOS 12.2.1. As far as Python is concerned, they have several installed, including 3.7, 3.8, 3.9, as far as I know mostly with pyenv. Robert

Is there anything below that error message? Pex should be saying what was inspected

and what does your repository set for the https://www.pantsbuild.org/docs/python-interpreter-compatibility#changing-the-interpreter-search-path … and would it include the interpreter you were expecting to be used?

Yeah. Almost good enough pattern matching, but the algorithm chopped a prefix

2.7.0_py39/lib/python3.9

@witty-crayon-22786, we currently do not have an interpreter search path set. So that’s definitely one thing we need to moving forward.

yea, possibly. the post that @fresh-cat-90827 wrote on this recently will probably help there: https://blog.pantsbuild.org/choosing-a-python-interpreter-for-a-pants-project/

Thanks for the pointer. I’m looking forward to reading it because that sounds like just what we need. Before trying Pants I read the entire documentation (for once) and the thing is: I can’t remember even seeing the search path option. Maybe that should be highlighted early on?!

in 2.9,

[python].interpreter_search_paths

was deprecated in favor of

[python-bootstra].search_paths

. Both still work in 2.9, but the former was removed in 2.10